1. Field of the Invention
The present invention relates to an ear folding apparatus that is available as an apparatus for folding ears of packaging material for cylindrical products (various types of sheet steel coils, aluminum coils and coiled sheet-like products of paper, rubber, vinyl, etc.).
2. Description of the Prior Art
In general, a metal strip coil 1 consisting of a steel strip is shipped after it has been regularly packaged by packaging material 2 for the purpose of rustproofing and scratch-proofing, as shown in FIG. 11. In the prior art, this packaging work has been achieved by hand. The coil has its outer circumference already wrapped by a packaging paper sheet in the preceding step of the process, ears 2a of the packing paper sheet are the folded and pleated, the central portion of the pleats are bent and stuffed into the coil bore, and finally the stuffed portion is fixed by sticking a tape or the like onto that portion. This packaging work necessitates a lot of labor and time, and hence automation of that work has been strongly required. Therefore, a number of automatic packaging apparatuses were proposed in the past.
(1) For instance, in Laid-Open Japanese Patent Specification No. 61-21313 (1986) is proposed an automatic packaging apparatus in which an ear of a packaging paper sheet for a coil is gripped at a plurality of points along its circumference and is bent towards the center of the end surface of the coil. At the same time the main body of the apparatus is moved towards the end surface of the coil, and the bent ear is pressed against the end surface of the coil to be folded thereon.
(2) Alternatively, Laid-Open Japanese Patent Specification No. 58-134824 (1983) proposes an automatic packaging apparatus in which, while a packaging paper sheet preliminarily shaped to have a cross-section configuration adapted for the shape of the coil, that is, a U-shaped cross-section configuration is being wrapped around an uter circumference of a coil, ears of the packaging paper sheet are folded.
In the case of the known apparatus described in numbered paragraph (1) above, folding devices equal in number to the number of pleats are required along the outer circumference of the coil and, moreover, since the structure and operation of the respective folding devices are complex, a high level of control technique is required. Accordingly, manufacturing cost becomes relatively high and maintenance of the apparatus is complex.
In the case of the known apparatus described in numbered paragraph (2) above, the entire apparatus is large. Because shaping of the packaging paper sheet into a U-shape in cross-section, wrapping of the packaging paper sheet around the outer circumference, and folding of the ears of the packaging paper sheet are performed at the same position, and the interval between preceding and succeeding equipment is then necessarily large the entire manufacturing line requires a large space. Also, application of the packaging apparatus to an existing manufacturing line is difficult. Furthermore, device for holding the pleats after folding and a device for bending and stuffing the folded ears into a coil bore are required separately.